Smartphone software and hardware become more sophisticated by the year. So a new device is expected to be faster than its predecessor. But it's a balancing act of both raw performance and power consumption. The A10 Fusion chip in the iPhone 7 series has four cores - two high-performance cores and two power-efficient cores to do just that. It's supposed to be the fastest A-series chip yet while not impacting battery life. So how does it really do on performance? Apple claims up to 2 times faster for CPU and 3 times faster for GPU compared to 2 generations ago (iPhone 6 series). Let's see if that's true.

GeekBench has been a standared in benchmarking CPU performance across many platforms. The 4.0.1 version that came out recently runs on iOS 9 or later, so I can only compare up to iPhone 4S. Still, you can see that iPhone 7 does indeed perform well. It is about 2.1 to 2.2 times faster than iPhone 6 Plus, and 35 to 40 percent faster than iPhone 6S Plus. We no longer have 2x performance jump like back in iPhone 5 - 5S transition, but things are in line with Apple's claim here.

When you upgrade to the latest high-end device, you would expect it to perform faster than the last one. Thanks to the ever-progressing technology this has always been the case with the flagship iPhones, but the performance jump was not always consistent. Let's see how the seven generations of the iPhones stack up.

One thing to note is that I'm probably not missing much by not having the original iPhone or iPhone 3G here. Many of the tests are already flaky with iPhone 3GS or 4, largely due to not getting a newer OS. 3GS at least is barely holding on with an OS that got its last security patch in February 2014. iPhone 3G is considerably worse, with its last update in November 2010, nearly five years ago.

First up is the GeekBench 3, as shown in the video. 3GS was able to run the 3.1.1 version of the benchmark on iOS 6.1.6, while the 4 ran the 3.2.0 version on iOS 7.1.2. All the others were running the latest version at the time of the writing, 3.4.0, which supports iOS 9.0.2 installed on the devices.

The results provide some interesting observations. There are two instances where the performance upgrade wasn't quite as significant as the other times: 3GS to 4, and 5S to 6 Plus. These were the times when the screen resolutions saw a significant jump from the predecessor - 360x480 to 640x960 and 640x1136 to 1242x2208 (downscaled to 1080x1920 on the display), respectively, which is about 4 times the pixel count. Much of the enhancements seemed to have sunk into supporting the higher display resolution.

In the other times, the performance increases approximately twofold each generation. At the transition from 4 to 4S, this was achieved purely by going dual-core. Since then the per-core performance was boosted. In the end, you can see an 11-fold improvement for going from the first dual-core iPhone (4S) to the latest (6S Plus).

iPhones and iPads have generally gotten big boost in speed with every new generation thanks to the enhancements in their processing units. But with iPhone 6 series, Apple decided to temper the pace. Instead of something like 2x boost, the CPU was to be up to 25% faster and GPU, 50%. This should just cover the boost in resolution, so I suppose Apple felt that the iPhone 5S was already fast enough in terms of user experience.

Indeed, with both iPhone 5S and 6 Plus running iOS 8.0 (and recently, 8.0.2), the general "feeling" of the speed was nearly the same, both mostly quick. It was just that iPhone 6 Plus happened to display the contents on a larger screen. Also, the amount of RAM staying at 1GB didn't have any noticeable impacts. On both phones, apps do run fine, although running RAM-heavy processes (notably Camera and Safari) tends to gracefully quit the other app in the background. The stopped app restarts quick enough when switched back.

To gauge some solid numbers, though, I did run through the usual batches of tests. All tests were run with iOS 8.0.2 and with same installed apps and settings.

First off, the boot time was measured. This is from when the screen turns on with the Apple logo to when the lock screen is loaded. iPhone 5S clocked in at 38.0 seconds, while iPhone 6 Plus was a bit faster at 30.6 seconds. The 5S got a bit slower than with iOS 7 installed.

Over the past four years, I have bought all the iPhones that had been officially released in Korea on the first day of domestic availability, starting with iPhone 3GS. iPhone 5S is the first one that I didn't wait. Of all those phones, iPhone 4 is currently on leave (dad is using it), so I have 3GS, 4S, 5, and 5S for simultaneous performance testing.

This may be something a lot of people would be curious about and I hope to give you a good basis in considering an upgrade for your previous generation iPhones. Read on and let's get started.